Few details were released by Causeway officials about the crash, which left the northbound lanes closed through the early-morning hours.

The U.S. Coast Guard said the 35-year-old black man has been missing since the accident. Additional details about the man were not released.

Causeway police and St. Tammany Parish deputies are assisting the Coast Guard and its boat and helicopter crews in the search.

Carlton Dufrechou with the Lake Pontchartrain Causeway said investigators believe the man was speeding, traveling at an excess of 100 miles per hour when he lost control of his motorcycle. Dufrechou said the man's motorcycle then slammed into the rear end of an SUV traveling in the right lane, and the man's body was apparently thrown off the left side. Dufrechou said the man fell between the north and southbound lanes into Lake Pontchartrain.

The other driver that was hit by the man's motorcycle was not injured, although her SUV was damaged in the process, according to Dufrechou.

Investigators are now in the process of reconstructing the incident to figure out exactly what happened.

"The Coast Guard sent out a couple of response boats to search the area. They also launched a helicopter crew to search from above to give us a better idea of the area. There are still searches going on," Lora Ratliff, a representative with the Coast Guard said.

Anyone with information is asked to call the Coast Guard at 504-365-2200.

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